Method of applying a self-adhesive waterproof membrane to an external wall and base slab of an underground construction

ABSTRACT

A method for applying a self-adhesive waterproof membrane to an external wall and base slab of an underground construction prior to the casting work includes applying a concrete layer on a working site and a protective layer on a diaphragm wall or retaining wall of the external wall, applying a rubbery asphalt waterproof membrane on the concrete layer and the outside of the protective layer. A rubbery asphalt layer of the membrane is facing directly to the underground structural body. A step of applying a protection concrete on the membrane that is applied on the concrete layer is added after the rubbery asphalt membrane applied step. Then, applying a steel frame or reinforcing steel to adjacent membrane and a formwork to an inner face of the external wall is added. Finally, pouring concrete to a space defined by the external wall and the formwork to allow direct contact of the rubbery asphalt of the membrane to the protection concrete and the concrete; and curing the concrete for around  7˜14  days to allow secure engagement of the waterproof membrane to the base slab and the external wall by capillarity induced by the solidfying process of the concrete so as to completely form a plant-root like waterproof layer to the concrete are added to complete the process.

FIELD OF THE INVENTION

[0001] The present invention relates to a method of applying a waterproof membrane to a base slab and external wall of an underground construction, and more particularly to a method that applies a self-adhesive waterproof membrane made of rubbery asphalt to the external wall and base slab of the underground construction. The rubbery asphalt will be melt to semi-liquid status when the external wall and base slab solidify to dissipate heat so that the molten rubbery asphalt is able to adhere to the external wall and base slab securely and therefore block the reticular external wall and base slab so as to accomplish the purpose of waterproof to the external wall and base slab of the underground construction.

BACKGROUND OF THE INVENTION

[0002] Due to the limited space available in metropolitan area, more and more buildings have underground constructions to function as parking lots, shopping malls, etc. However, unlike the constructions above ground, that are seldom influenced by moisture, the constructions underground are always influenced by moisture. The underground moisture often infiltrates into the interior of the underground construction to cause the interior space damp. It is well known in the art that when a space is damp, it is not suitable for people to live or store objects. The danger of the underground water has become an increasing threat to the underground construction. Therefore, how to keep water out of the underground construction so as to provide a dry, useful and safe space has become an important lesson.

[0003] Currently there are two different methods to prevent water from infiltrating into the underground construction, the drainage and the water block-up.

[0004] The drainage method is easy to implement, however, the amount of water drained is limited. To the area where large amount of constructions are dense and the soil is sensitive to soil settlement or displacement, the drained water may cause a great soil settlement or soil displacement. Based on the threat, large construction often adopts the water block-up method to accomplish the purpose of waterproof.

[0005] The water block-up method is generally implemented to the external wall and the base slab of an underground construction and there are two ways of implementing the water block-up, one is the pre-coating of plastic waterproof membrane and the other is the pre-coating of self-adhesive waterproof membrane. The two methods of implementing the water block-up method is basically the same. The difference lies on the material of the membrane, which influences the waterproof effect. The following is an explanation to the implementation of the two different methods.

[0006] Pre-coating plastic waterproof membrane

[0007] With reference to FIG. 1, an underground construction 1 has a base slab 11, an concourse slab 12, a top slab 13 and an external wall 14. The plastic waterproof membrane 2 is made of high molecular polymer, which makes the membrane 2 elastic and good acid and alkaline resistance so that after the membrane 2 is adhered to the external wall and the base slab, the external wall and the base slab have great waterproof ability.

[0008] The step(s) for implementing the method is to first prepare a concrete layer 21 on the base slab and a protective layer 23 on a diaphragm wall or retaining wall 15 of the external wall 14. The membrane 2 is implemented on the concrete layer 21 and the outside of the protective layer 23. On the membrane 2 implemented on the concrete layer 21, a protection concrete 22 is formed. Then, adjacent to the side of the membrane 2 and the top of the protection concrete 22, steel frame (not shown) is installed to become the underground construction 1. With such an arrangement, the membrane 2 is able to directly contact the protection concrete 22 and the protective layer 23 so as to form a waterproof layer for different concrete layers.

[0009] Pre-coating self adhesive waterproof membrane

[0010] With reference to FIG. 2, the plastic waterproof membrane 3 is made of high molecular polymer, which makes the membrane 3 elastic and good acid and alkaline resistance so that after the membrane 3 is adhered to the external wall and the base slab, the external wall and the base slab have great waterproof ability.

[0011] The step(s) for implementing the method is to first prepare a concrete layer 31 on the excavation site and a protective layer 23 on a diaphragm wall or retaining wall 15 of the external wall 14. The membrane 3 is implemented on the concrete layer 31 and the outside of the protective layer 33. On the membrane 3 implemented on the concrete layer 31, the protection concrete 32 is formed. Then, adjacent to the side of the membrane 3 and the top of the protection concrete 32, steel frame or reinforcing steel (not shown) is installed to accomplish the underground construction 1. With such an arrangement, the membrane 3 is able to directly contact the protection concrete 32 and the protective layer 33 so as to form a waterproof layer for different concrete layers.

[0012] Following is a comparison table showing the advantage and disadvantage of the two methods above. TABLE 1 Pre-coating Pre-coating plastic self-adhesive Item waterproof membrane waterproof membrane 1. Implementing X O technique for connec- tion of the membrane 2. Adaptability of O O material used on the base slab 3. Adaptability of X O material used on the external wall 4. Adaptability of O O material used on the top wall 5. Project cost Δ O 6. Stability and water- Δ O proof characteristic of the membrane 7. Domestic performance O Δ 8. Foreign performance O O 9. Back-up engineering X O when there is a failure in the implementation of the membrane 10. Environmental pro- X O tection and safety feature

[0013] From the comparison above, it is noted that the pre-coating self-adhesive waterproof membrane has better performance.

[0014] In general, the waterproof engineering to the underground construction is limited to the soil condition of the area where the working site is located and the worker is forced to implement the pre-coating waterproof membrane to achieve the waterproof effect. The waterproof membrane normally is chosen from PVC membrane, asphalt-polystyrene membrane, acetate-polystyrene . . . etc. No matter what kind of method is chosen for pre-coating waterproof membrane and what kind of material is chosen for the waterproof membrane, the conventional method is not satisfactory to meet the modem needs.

[0015] After the conventional method for implementing the waterproof membrane is finished, more or less there is seep in the base slab and the external wall. In order to keep the interior of the underground construction dry, effective measure to eliminate water seeping is a must. However, to capture or patch the place where the water seep occurs is somewhat difficult and the project cost for capturing and patching the water seep often exceeds the original budget, which causes the uncertainty of the overall cost. Therefore, the construction industry often takes budget raising as a pretty common situation. The difficulties for capturing and patching the water seepage may be concluded as follows:

[0016] 1. There is no complete contact between the waterproof membrane and the concrete body.

[0017] 2. There are a lot of micro pores in the concrete body and when the water seeps into these pores; and flows around, it is almost impossible to tell where the water is coming from.

[0018] 3. Because there is no certain way to pin point where the water is from, trial-and-error is often adopted to search for the exact location where the water infiltrates and seeps.

[0019] Recently, the waterproof membrane produced by U.S. company called “GRACE” does have superior performance in waterproof effect when compared with the conventional method and whose back-up engineering is much easier. However, the ingredient of the membrane is unique and the cost is high, therefore, the overall construction cost is impossible to be reduced, which is a mission impossible for the construction industry trying to upgrade the waterproof effectiveness with a low cost.

[0020] To overcome the shortcomings, the present invention intends to provide an improved method implementing waterproof membrane to mitigate or obviate the aforementioned problems.

SUMMARY OF THE INVENTION

[0021] The primary objective of the invention is to provide a method that applies a self-adhesive waterproof membrane made of rubbery asphalt prior to the construction of external wall and base slab of the underground structure. The rubbery asphalt will be melt to semi-liquid status when the external wall and base slab solidify to dissipate heat so that the molten rubbery asphalt is able to adhere to the external wall and base slab securely by means of capillarity to drain the excessive water in the concrete and therefore block the porous surface of external wall and base slab so as to accomplish the purpose of waterproof to the external wall and base slab of the underground construction.

[0022] Another objective of the invention is to provide a method to apply a rubbery asphalt that is able to be melted to a semi-liquid state so that the molten rubbery asphalt is able to adhere to the base slab and the external wall in an irregular manner so as to block water seep effectively.

[0023] Still, another objective of the invention is to provide an improved method using easy accessible low-priced rubbery asphalt to replace with high-priced waterproof membrane.

[0024] Another objective of the present invention is to provide a method that has no heat welding requirement, longer working period, special tools to perform tests (penetration and vacuum tests), poisonous gases generation while performing heat welding . . . etc.

[0025] Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026]FIG. 1 is a schematic view in partial section showing a conventional method for applying a pre-coating waterproof plastic membrane;

[0027]FIG. 2 is a schematic view in partial section showing another conventional method for applying a self-adhesive waterproof membrane;

[0028]FIG. 3 is a schematic view in partial section showing a preferred embodiment of the implementation of the method of the present invention;

[0029]FIG. 4 is a partially enlarged schematic view showing the adhesion of the rubbery asphalt to the base slab and the external wall;

[0030]FIG. 5 is a schematic view in partial section showing another preferred embodiment of the implementation of the method of the present invention; and

[0031]FIG. 6 is a partially enlarged schematic view showing the adhesion of the rubbery asphalt to the base slab and the external wall.

DETAILED DESCRIPTION OF THE INVENTION

[0032] With reference to FIG. 3, the present invention is to provide an improved method for applying a waterproof membrane prior to the construction of the base slab and the external wall of an underground structure 1. The underground construction 1 normally has a base slab 11, an concourse slab 12, a top slab 13 and an external wall 14.

[0033] The step for applying the method comprises:

[0034] (a) applying a concrete layer 14 on the working site and a protective layer 43 on a diaphragm wall or retaining wall 15 of the external wall 14;

[0035] (b) applying a rubbery asphalt waterproof membrane 4 on the concrete layer 41 and the outside of the protective layer 43; wherein a rubbery asphalt 40 that is made of the membrane 4 is facing directly to the underground structure;

[0036] (c) applying a protection concrete 42 on the membrane 4 that is applied on the concrete layer 41;

[0037] (d) applying a steel frame or reinforcing steel (not shown and numbered) to adjacent membrane 4 and a formwork to an inner face of the external wall 14;

[0038] (e) pouring concrete to a space defined by the external wall 14 and the formwork to allow direct contact of the rubbery asphalt 40 of the membrane 4 to the protection concrete 42 and the concrete; and

[0039] (f) curing the concrete for around 7˜14 days to allow secure engagement of the waterproof membrane 4 to the base slab 11 and the external wall 14 so as to completely form a waterproof layer to the concrete.

[0040] During the curing process, the concrete dissipates heat at about 45˜60° C. The boiling point of the rubbery asphalt 40 is at about 70˜80° C. Therefore, the rubbery asphalt 40 is resilient and has a fixed appearance at room temperature. When the temperature rises to 40° C., the rubbery asphalt 40 begins to melt to semi-liquid state. Accordingly, the present invention uses this feature of the rubbery asphalt 40 to securely engage with the base slab 11 and the external wall 14 of the underground construction 1.

[0041] In step (e), using the dissipated heat from the concrete of the base slab 11 and the external wall 14 during the curing process is able to melt the rubbery asphalt layer of membrane 4 so as to release the semi-liquid rubbery asphalt 40. The semi-liquid rubbery asphalt is viscous so that when it flows through the concrete, a part of the rubbery asphalt 40 stays and then penetrate into the porous surface of the concrete structure. The main reason for the penetration of the rubbery asphalt 40 is that the capillarity occurred on the concrete face expelling water contained inside the concrete during the curing process, the others are the soil pressure from outside of the wall, the earth reaction from the base slab and the self weight of the structure , etc. Therefore, the semi-liquid rubbery asphalt 40 is able to penetrate into the face of the protection concrete 42 and the external wall 14. After the heat dissipation is over and the concrete is cooled down, the semi-liquid rubbery asphalt 40 starts to return to its original state. When the recovery of the rubbery asphalt is over, the rubbery asphalt 40 is able to adhere to an outer face of the concrete of the external wall 14 and the base slab 11 securely engaged with the protection concrete 42.

[0042] With reference to FIG. 4, when the semi-liquid rubbery asphalt 40 of the waterproof membrane 4 adheres the external wall 14 and the protection concrete 42 of the base slab 11, the rubbery asphalt 40 has extensions 401 extending out like the plant root. The extensions 401 fill the porous surface of the external wall 14 and the protection concrete 42 so that after the semi-liquid rubbery asphalt 40 returns to its normal state, the porous surface of the external wall 14 and the protection concrete 42 has a effective waterproof layer.

[0043] With reference to FIG. 5, another preferred embodiment of the present invention is shown, wherein the step (c) of the method shown above is able to be neglected. That is, the protection concrete 42 on top of the membrane 4 is not necessary so that in step (e) the rubbery asphalt 40 is able to have direct contact to the concrete. With such an arrangement and after the concrete curing process, the solidified rubbery asphalt 40 is able to have direct contact with the external wall 14 and the base slab 11.

[0044] With reference to FIG. 6, when the semi-liquid rubbery asphalt 40 of the waterproof membrane 4 adheres the external wall 14 and the base slab 11, the rubbery asphalt 40 has extensions 401 extending out like the plant root. The extensions 401 fill the pores of the surface of the external wall 14 and the base slab 11 so that after the semi-liquid rubbery asphalt 40 returns to its normal state, the porous surface of the external wall 14 and the base slab 11 has an effective waterproof layer.

[0045] In the embodiment of the present invention, the waterproof membrane 4 is composed of a rubbery asphalt 40, a polyester with high density or a layer of fiber or a layer of polyester polymer. The rubbery asphalt 40 may be added with gravel, aggregates 5, slag or the like to increase the adhesion with the concrete. The rubbery asphalt 40 may be added to a single face of the waterproof membrane 4 or both side faces of the waterproof membrane 4.

[0046] The waterproof membrane of the present invention has an adhesion intensity with the concrete, which is up to 2.3 kg/cm. When gravel is added to the membrane, the adhesion intensity is increased to 2.4 kg/cm. From the following test tables, it is known that the adhesion intensity is well above the 1.0-2.0 kg/cm, the standard value. TABLE 2 Test name: adhesion intensity of the pre-coating self-adhesive waterproof membrane to concrete Test date: Nov. 5, 2001 Test method: the membrane is orthogonal to the concrete Test item Test result Single (no gravel) intensity A1 (kg/cm) 2.56 Single (no gravel) intensity A2 (kg/cm) 2.46 Single (no gravel) intensity A3 (kg/cm) 2.35

[0047] TABLE 3 Test name: adhesion intensity of the pre-coating self-adhesive waterproof membrane to concrete Test date: Oct. 26, 2001 Test method: the membrane is orthogonal to the concrete Test item Test result Single (with gravel) intensity A1 (kg/cm) 2.4 Single (with gravel) intensity A2 (kg/cm) 3.4 Single (with gravel) intensity A3 (kg/cm) 2.4

[0048] Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

What is claimed is:
 1. A method for applying a self-adhesive rubbery asphalt waterproof membrane to an external wall and base slab of an underground construction, the method comprising: (a) applying a concrete layer on a working site and a protective layer on a diaphragm wall or retaining wall of the external wall; (b) applying a rubbery asphalt waterproof membrane on the concrete layer and the outside of the protective layer, wherein a rubbery asphalt from the membrane is facing directly to the underground construction; (c) applying a protection concrete on the membrane that is applied on the concrete layer; (d) applying a steel frame or reinforcing steel to adjacent membrane and a formwork to an inner face of the external wall; (e) pouring concrete to a space defined by the external wall and the formwork to allow direct contact of the rubbery asphalt of the membrane to the protection concrete and the concrete; and (f) curing the concrete for around 7˜14 days to allow secure engagement of the waterproof membrane to the base slab and the external wall so as to completely form a waterproof layer to the concrete.
 2. The method as claimed in claim 1, wherein the rubbery asphalt has extensions flowing to porous structure of the protection concrete and the concrete so as to form a waterproof layer to the base slab and the external wall and block the porous structure.
 3. The method as claimed in claim 1, wherein in the curing process of the concrete, the concrete dissipates heat at a temperature about 45-60° C. to melt the rubbery asphalt.
 4. The method as claimed in claim 3, wherein the molten rubbery asphalt is adhered to the base slab and the external wall by capillarity.
 5. A method for applying a waterproof membrane to an external wall and base slab of an underground construction, the method comprising: (a) applying a concrete layer on the working site and a protective layer on a diaphragm wall or retaining wall of the external wall; (b) applying a rubbery asphalt waterproof membrane on the concrete layer and the outside of the protective layer, wherein a rubbery asphalt that is from the membrane is facing directly to the underground construction; (c) applying steel frame or reinforcing steel to adjacent membrane and a formwork to an inner face of the external wall; (d) pouring concrete to a space defined by the external wall and the formwork to allow direct contact of the rubbery asphalt of the membrane to the concrete; and (e) curing the concrete for around 7˜14 days to allow secure engagement of the waterproof membrane to the base slab and the external wall so as to completely form a waterproof layer to the concrete.
 6. The method as claimed in claim 5, wherein the rubbery asphalt has extensions flowing to porous structure of the protection concrete and the concrete so as to form a waterproof layer to the base slab and the external wall and block the micro pores on the surface of structure.
 7. The method as claimed in claim 5, wherein in the curing process of the concrete, the concrete dissipates heat at a temperature about 45-60° C. to melt the rubbery asphalt.
 8. The method as claimed in claim 7, wherein the molten rubbery asphalt is adhered to the base slab and the external wall by capillarity. 